Gurgaon vat- certificate & online access

Dear Friends, I am register VAT dealer in Gurgaon. I applied for VAT because of online business and used a recommended CA by Amazon. As I don't stay in India and so I used all his services on agreed terms and payments. He took my Certificate back by giving some reasons that he need to get some amendment done and apply for OTP. Later after few weeks when I asked he is not returning neither certificate not sharing online details about my VAT. Can you please guide how can I bypass him to get my certificate and access to online so that it should not be misused. Please suggest as I am new to the India sytems